Littmann Stethoscopes Patented Tunable Technology

Tunable technology provides convenience, versatility, and enhanced acoustics. Its dual frequency diaphragm combines both bell (low-frequency) and diaphragm (high-frequency) into a single side of the chestpiece. You control bell and diaphragm modes by pressure on the chestpiece rather than turning it over.

Bell Mode (low-frequency)		Diaphragm Mode (high-frequency)

Bell Mode (low-frequency)

For low-frequency sounds, light contact is used on the chestpiece. The diaphragm membrane is contained by a flexible surround that actually suspends it, allowing the membrane to resonate low-frequency sounds.

Diaphragm Mode (high-frequency)

For high-frequency sounds, firm contact pressure is used on the chestpiece. By pressing on the chestpiece, the diaphragm membrane moves inward until it reaches an internal ring. The ring simply restricts the diaphragm membranes's movement. It blocks, or attenuates, low-frequency sound and allows you to hear the higher frequency sounds.
    No other stethoscope gives you the same quality and efficiency in auscultation. How? Because only 3M has the patented, tunable diaphragm technology which allows you to alternate between low and high-frequency sounds without removing the chestpiece. Whether you choose the versatility of the 3M™ Littmann™ Cardiology III Stethoscope or the ultimate acoustics of the 3M™ Littmann™ Master Cardiology Stethoscope, you can always expect the best in a Littmann stethoscope.